# In General Relativity, what would happen to the Earth the Sun disappeared?

In summary: The curvature of space-time would cause the disturbance in the gravitational field to travel at the speed of light. So even if the sun were taken far away, the Earth would still be in it's original orbit for 8 minutes. Right. The curvature of space-time would cause the disturbance in the gravitational field to travel at the speed of light. So even if the sun were taken far away, the Earth would still be in it's original orbit for 8 minutes.
I'm not sure if this is in the right forum.

If the Sun disappeared, would the Earth's velocity change? Since the space-time fabric would 'spring' back into it's normal position, the effect of gravity on the Earth would dissipate? Thus, resulting in the Earth being thrown out of it's orbit?

I'm not sure if this is in the right forum.

If the Sun disappeared, would the Earth's velocity change? Since the space-time fabric would 'spring' back into it's normal position, the effect of gravity on the Earth would dissipate? Thus, resulting in the Earth being thrown out of it's orbit?

What orbit? If the sun disappeared, then 8 minutes later the Earth would HAVE no orbit because it would have nothing to orbit AROUND. It would just keep going in whatever direction it was headed in 8 minutes after the sun disappeared.

phinds said:
What orbit? If the sun disappeared, then 8 minutes later the Earth would HAVE no orbit because it would have nothing to orbit AROUND. It would just keep going in whatever direction it was headed in 8 minutes after the sun disappeared.

Yes, I know that, but what I'm asking is, would it's velocity change since there's no gravity acting upon it from the Sun which has disappeared?

You're going to end up in a logically self-contradictory position if you try to answer this question within GR. GR has local conservation of mass-energy, and therefore it doesn't allow the sun to disappear. GR becomes logically inconsistent if you assume violation of conservation of mass-energy.

If the sun was suddenly ripped out of the solar system and taken far away, GR says that the disturbance in the gravitational field would travel at c, so the Earth would continue in its original orbit for another 8 minutes.

bcrowell said:
You're going to end up in a logically self-contradictory position if you try to answer this question within GR. GR has local conservation of mass-energy, and therefore it doesn't allow the sun to disappear. GR becomes logically inconsistent if you assume violation of conservation of mass-energy.

If the sun was suddenly ripped out of the solar system and taken far away, GR says that the disturbance in the gravitational field would travel at c, so the Earth would continue in its original orbit for another 8 minutes.

Thanks, that has helped me a lot. By gravitational field, I assume you're referring to the curvature of space-time?

Thanks, that has helped me a lot. By gravitational field, I assume you're referring to the curvature of space-time?

Right.

## 1. What is General Relativity?

General Relativity is a theory developed by Albert Einstein in 1915, which describes the gravitational force as a curvature in the fabric of space and time. It is considered one of the fundamental theories of modern physics.

## 2. How does General Relativity explain the motion of objects?

According to General Relativity, objects with mass cause a curvature in space and time, which affects the motion of other objects around it. This explains why planets orbit around the sun and why objects fall towards the Earth.

## 3. What would happen to the Earth if the Sun disappeared?

If the Sun disappeared, the Earth would continue to move in a straight line, but due to the curvature of space and time, it would follow a curved path and eventually escape the solar system. This is because the Sun's mass would no longer be there to cause a curvature in space and time.

## 4. Would the Earth experience any immediate effects if the Sun disappeared?

No, the Earth would not experience any immediate effects if the Sun disappeared. This is because the effects of gravity travel at the speed of light, so it would take about 8 minutes for the Earth to feel the absence of the Sun's gravitational pull.

## 5. Would General Relativity still hold true if the Sun disappeared?

Yes, General Relativity would still hold true even if the Sun disappeared. This theory explains the fundamental principles of gravity and the curvature of space and time, regardless of the existence of a particular object, such as the Sun.

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